/* eslint-disable */
let _Vue = null
export default class VueRouter {
    //静态方法 _install
    static install(Vue) {
        //1.判断当前插件是否安装
        if (VueRouter.install.installed) {
            return
        }
        VueRouter.install.installed = true
            //2.把vue 构造函数记录到全局变量
        _Vue = Vue
            //3.把创建的vue实例的创建到router对象注册到Vue 实例上
            //混入方法 让 this.$options.router this指向
        _Vue.mixin({
            beforeCreate() {
                //beroreCreate 执行很多次 判断当前选项是否有router
                if (this.$options.router) {
                    _Vue.prototype.$router = this.$options.router
                    this.$options.router.init()
                }
            }
        })
    }
    constructor(options) {
        this.options = options
        this.routeMap = {}
        this.data = _Vue.observable({
            current: '/'
        })
    }
    init() {
        this.createRouteMap()
        this.initComponents(_Vue)
        this.initEvent()
    }
    createRouteMap() {
        // 遍历所有的路由规则 把路由规则解析成键值对的形式 存储到routeMap中
        this.options.routes.forEach((route) => {
            this.routeMap[route.path] = route.component
        })

    }
    initComponents(Vue) {
        Vue.component('router-link', {
            props: {
                to: String
            },
            render(h) {
                return h("a", {
                    attrs: {
                        //href: this.to
                        href: '#' + this.to
                    },
                    on: {
                        click: this.clickhander
                    }
                }, [this.$slots.default])
            },
            methods: {
                clickhander(e) {
                    window.location.hash = '#' + this.to
                        //history.pushState({}, "", this.to)
                    this.$router.data.current = this.to
                    e.preventDefault()
                }
            }
            // template: '<a :href="to"><slot></slot></a>' 
            //完整版vue  vue.config.js 配置 runtimeCompiler: true
        })
        const self = this
        Vue.component("router-view", {
            render(h) {
                // self 当前render 函数的this需要改变
                const component = self.routeMap[self.data.current]
                return h(component)
            }
        })
    }
    initEvent() {
        // window.addEventListener("popstate", () => {
        //     this.data.current = window.location.pathname
        // })
        window.addEventListener('load', this.hashChange.bind(this))
        window.addEventListener('hashchange', this.hashChange.bind(this))
    }
    hashChange() {
        if (!window.location.hash) {
            window.location.hash = '#/'
        }
        this.data.current = window.location.hash.substr(1)
    }
}